Train stop and signal system



vWiardi 5, 1929. R, v APPLETON 1,704,116

TRAIN sToP AND SIGNAL SYSTEM Filed April 13, 1927 s sheets-sheet 1 March 5, 1929.

' R. v. APPLETON TRAIN STOP AND SIGAL SYSTEM Filed April l5, 1927 5 Sheets-She@ @www @N N N NSN 1Q .wf S\ im ALU mw Z mf Mrchs, 1929. "R v, APPLE-TON u 1,704,116

TRAIN STOP AND SIGNAL SYSTEM Filed April 134, 1927 5 Sheets-Sheet 3 @UGG mk u I a l 1 wTL/; O @sie @R raf Y switch 'inthe cab. Means in the cab ispro- Patent-ediMar. 5, 1929.

'UNlTE-"DLSTATES .PATENT orifice; Y

RUSSELL v. APPLETON, or 1tranen/'oon,v cannoni-WIA,

TRAIN sror. AND' sIGnAL SYSTEM.

` Application-mea Aprnia, 1927. serial No. 1253,340.

'This invention relates toan improved in-i' ductive train stop system, and more particularly to the combination' with a block signal system vof a single element train stop,

and position indicating mechanismin the locomotive' cab, designed to'give the operator a closer vision of track' conditions and stop locations, and to doubly warn of theapproach to occupied territory by signals, and. brake. applications, which can be res'et lwhile running. undercautionconditions only,

but under stop conditions can only be reset i after. the vehicle is brought to a complete halt.

' Briefly described, the system provides means whereby a wayside track caution signal is given at the entrance to the 'block ;pre-

- ceding the block occupied by a t'rain or other obstruction. In addition, a caution indication` signal is given in the cab, not only in the first block preceding` the oe.- eupied block,' but also a *repeating cauwhich must bemanipulated bythe operator i ofthe-train, in combination with cab colored..lights indicating the advance .conditionj'f, n the track` and 'brake application points, so thatl the operator may forestall' an automatic `brake application if alert at the brake application points. Another object is to provide an apparatu of this type in which the trainv when stopped cannot be started again without properly e tien signal for prior acknowledgment byv the operator is given in the second preceding block at the entrance to which the usual proceedr signal is' displayed at the wayside. At the exitend of each of tlietwo blocks lpreceding the occupied block, a stop signal will be flashed-in the cab, and a brake application'Will take place unless forestalled by a manually operatedl acknowledgment,

lvided-` whereby the brakes maybe released and.` reset if their application is not forestalled 'in time, provided the train is inere- -ly in afcaution block., but the brakes can only be reset after the train is completely 4halted in case the train is in a stop block or an obstruction occurs in the block thenoccupied by the train.A To accomplish the polarity current to a portion of the block,

above, one track and one line'relay for each block are used to furnish, from a singleY alternatingcurrent source, either normal polarity current to the entire block, or adverse according to track conditions., The wayside semaphore 'signal systems also'are -actuated from the same'power source. AV sinf 'gle power source on the locomotive furnishes currenttor the brake releasing means, and

' the signal lights in the cab, these being conltrclled` by a relay energized through an amplifier from current induced from the tracks,

l and also by certain acknowledgment switches knowledgment switch.

setting the'en'gineers brake valve and ,then

manipulating xedreleasingmeans, located below the locomotive. l

' Another obfect isto-provide an improved amplifying circuit by means of which the electrical energy induced from the track is amplied and vconverted. into two control circuits for ener Another4 object is to provide-novel a-l sudden change in track conditions occur, a brake "application willv immediately take place insteadof waiting until the next intermittent brakingpont is occupied.

gizi-ng the controllingfr'elay' '011' the' locomotive. a

means whereby, when the engine passes over a clear' i lnterrnittentbraking lpoint on the track, and

Another object is to providel anapparatus of this class` in which the operatlnby controlling the forestalling switch-can continue when the. train .occupiesXl non-electrified track.

AAnother lobject istoprovide meansor supplying one pulsating current to the track railsv with triple controlling characteristics.'

Another 'object is to provide such anapparatus whereinl a caution signal is given' prior to. the necessity for use of the ac- Another object is to providev such an apparatus wherein la brake application occurs uponuforeign current interference. l.

Other objects and advantages of this infvention will'be apparent from the follow-v ing detailed .descriptonofonesystem and combination of parts. involving the principles of this invention. l

In the accompanying drawings: t

Fig. 1 is a diagrammatic layout showing -the track-apparatus, the wayside signals,

and. the operating circuits therefor;

Fig. 2 isa diagrammatic illustration of the mechanism carried by the locomotive, ,includmg the 'mechanism for receiving and amplifying the control current from the track- Way, the bra-ke control mechanism, the position-,indicating signals in the cab, and the control circuits for this mechanism.

Fig. 3 is a detail sectional View of a modied form of acknowledgment switch.

Fig. 4 is a view illustrating diagrammatically and in detail perspective a form of rotary interrupter for providing -the pulsatv-t-hejrelation between the various alternat-4 ing direct current from the originalalternating current.

Fig. 5 isav series of diagrams'illustrating ing, pulsating and induced currents.

Referringiirst to Fig. 1, a stretch Vof trackway is indicated, along which traiiic will normally proceed-in the direction of the arrows, this trackway comprisingthe rails R andy R, each rail being separated at in# tervals by insulation 1, so that the trackway is divided into a series of' similar sections or blocks, each bloclbeing insulated from the adjacent blocks. The individual rails composingeach line of track-rail Rjand R:`

may be suitablyfbonded together, especially at frogs or cross-overs, so that each rail will form a continuous conductor from one end of the block to the other. The several blocks will normally be" of substantially equal lengths, for example, about 4000 feet, 'although this length may. be eitherincreased.A or' decreased without departing from the principles oftheinvention. In Fig. 1 we have illustrated parts of four blocks, including the entrance `end of block 1, all of blocks 2 and 3, and the exit endotblock 4. Blocks 1, 2 and 3 are designated as a ,stop`block,a caution block, and a proceed bloclqrespectively, these terms berent throughthe conductors 2 and 3 to the main`line conductors 4. and 5 Whichextend substantially parallel with' the blocks.l Ineach block-the traii'ic signalling several apparatus and circuits'therefor are indentif cal With the apparatus and circuits therefor tions in one block will sufice for all. As here shown, the apparatus and connections in every other block. Therefore, a detailed ,description of the apparatus and .connecassociated with the ent1"ance.end of block 1 l and the exit end of block 2, are indicated by unprimed reference characters, the .cor-

responding parts for blocks 2.and 3 being indicated by primed reference characters,

and the similar reference characters for`- blocks 3 and `4 heilig'double-'primed The primary Pof a'transformer located i adajacent the exit end of block 2, Iis energized through leads 6I and 7 extending to the main powerlines 4 and 5, respectively.

This transformer-has a signal secondary SS A andtwo similar ltrack secondaries TS and RS. The polarizedl three-position line relay `C, which is an induction motor relay with two energizing circuits, has a pivoted n three-position armature 8a adapted to open or close a `signal circuit hereinafter de# scribedand also a pair of similar threeposition pivoted armatures 8b and 8c. The

armatures 8, 8band 8c will be' swung'to the right lWhen vcoil 8 of relay C is receiving so? ca led normal polarity current, and will be reversed orfswung to the le'ft when the rela is receiving adverse polarity current.

'T1 1e coil 8x of relay C is constantly energized by aIternatingcurrent derived Jfrom the signalv secondary SS. Vhen the relay C isfdeenergized, the armatures 8a, 8b and 8c will fall to a third or intermediate position.

The coil 11 of a track relay D is connected .by Wires 9 and 10 across the rails R and Rv 'at the entranceend of block. 1. .The relay D is provided with a neutral yarmature having three contactbars 11, 11b, -and 11, respectively, ywhich are each held up to one lcircuit-making posit-ion When the relay D is' energizedand fall to a different position when the relayis deenergized.'.

An interrupter K (shown in detail perspective in Fig. 4, and indicated diagrammatically in-Fig. 1),'is utilized to convert alternating current inducedA from the" primary P into a pulsating direct current in the rails R and R. In the form indicated,` a coil v200 is mountedto rotate between the poles o-a stationary permanent magnet 201. Alternating current from the signal secondary SS is supplied through resistance 202, and the slip-rings 203 to the armature coil 200. A-pair of similar interrupter discs 204 and'205'are mountedon the' shaft of the motor which drives theinterrupter, each` d disc comprising a contact section 206, 90o in arcuate length and an insulating section 270" in length indicated at 207. The two discs are arranged so that the Contact sec tions 206 are 180O out of l phase with each other, as indicated in the drawings. One

v lterminal of" secondary TS is yconnected through Wire 207"with a lbrush or sliding contact 208 'bearing on the disc 204, theother terminal of this secondary being connected throughwire 19 with the arma-ture 8c of relay CL The secondary RS is connected in series with'the primary oi. transformer 209, so that the'current inducedain the secondary -of this transformer -willh'e' similar to the current from secondary T S but 180 out of phase therewith. One terminal of the secondary of transformer-209 is'connected TS, and the sine-wave shown'in brokenl lines through wire 210 with brush 211 bearing on disc 205.v lThe' other terminal ot" this secondary is `connected to wire y19 leading to the armature 8.l The other brushes 212 and 213 bearing respectively on the contact discs`20l and 205, yparallel with the brushes 208 and 21,1',r are connected by wire 12 withthe armature-8P of the relay C.

Reerring now to diagram (1) of Fig. 5,

y the sine-wave designated TS indicates the alternating current induced in the secondary and designated RS indicates the. alternating current derived from the transformer 209, this current being 180O out of phase with the' current in secondary Thev discs204- and 205 of the rotaryy synchronous interrupterjare so set'` that they will cut outthreequartersof each cycle of each current, and

` retain only what may be termed the rising pulsations v half ofthe positive sdeof each cycle, as indicatedvby the shaded areas in diagram (1),.and by the solid lines in diagram (2),

vwhich latter indicates graphically the pulsating direct current that 4will be transmitted through wires 12 and 19 to the arma- 'tures of relayC, adthence to the rails R and R', as `hereinafter described. It Will be 'noted thatthis current consists of a series of similar rising pulsations, eacho which is suddenly cut off at its peak, there being a dead interval'corresponding to the length of one pulsation between each of the successive Under normal conditions, .that is, with each of the two advance blocks unoccupied,

'- the armatures 8, 8b, and` 8c will be swung' over to the right as hereinafterdescribed, as lindicated inv dotted lines for block 1, or as indicated in solid lines at the left lhand side l of 1 .for block 3. At such timesa norrighthandA contact 13,wire 14, connections- 'relay D', wire 10', rail;R'connection 16 ad- 1 mal polarity pulsating current` will flow from either the track secondary TS or tra-nsformer 209, and vthe interri'ipter K, through Wire 12 tothepivot end of armature 8b,

15 to rail R adjacent the insulation 1 at the exit end of block: 2, through ,rail R to the entrance end of 'block 2, wire 9, coil 11'of jacent the'exit end ofblock `2, wire 17 right hand contact 18, armature 8, and Wire 19,

connected .to the pivot end of this armature after described, the armatures 8b and 8c will be swung to the left (as indicated in full lines for hlock2), and an adverse polarity track circuit will be completed as follows:

`Track secondary TS or transformer 209, interrupter K, wire 12, armature 8b,.left'hand contact 20,.wire 21, wire 22, to connection 23 to rail R', rail R" to the entrance end of block 2, wire 10', coil 11 of relay D',- wire 9', rail R, connection 24,- (opposite connection 23), wire 25 to left hand contact 26, y

armature 8,'and lwire .19 back to the track secondary TS or the transformer 209. This adverse polarity pulsating current may" be indicated graphically by the broken lines in diagram (2) of F ig. 5.- The track connec-4 tions 23 and 24 are spaced a suitable dis- '.tance, for example, about twenty'feet, from the insulations 1 at the exit end of block 2, so that a dead 'space ofthis length is provided adjacent the exit; end of the block, to which no current is supplied suitable for actuating the locomotive controldevices when the normal polarity current-is cut eti", and

adverse polarity current is being'supplied to` theftracks.` The circuit last described may be termed a. caution adverse polarity partial-block-length current.y

by the arinatures'8land 8c, when relay Chis 30, respectively, with the wires22 and 25, so that operatively the sam'e caution adverse 'polarity circuit described hereinabove .will be completed when the 4relay C is deener-w gized, and the'armatures 8" and 8c arein their intermediate positions. This may be termed a repeating caution circuit.

T hewa side siffnals S S" and S" are here shown as ofan Aordinary semaphore type, actuated by a-pair of coils Bland 32.

The semaphore S is shown in stop position, the semaphore S in caution position, and the semaphoreS" in' proceed position. vA. current `iio'ws when. relay D is The intermedii' late contacts 27 and 28, which are engaged deenergized, are connected by wires 29 and f iio energized. from signal secondary SS through wire 33, armature 11, upper contact 34;, wire 35, signal 'coil- 31, and wire 36, back to the signal secondary SS. A. similar parallel current iiowsrfrom wire 35 through wire 37, armature 8a of relay G, contact 38 or 38 when relay C is properlyeneigizei wire 39, y

signal coil 32, and thence over wire 36 backto the signal secondary SS. vWhen relay D 'is deenergized, as shown at the right of Fig.

1, the armature 11a will fall and break the circuits to both signal coils 31 and 32' and the semaphore will fall to stop position, as indicated at S. When relay D is energized but relay C is d'eenergized (as indicated in.

block 2), the circuit throughsignal coil 31 will remain complete, but the circuitthroughl signal coil32 will be broken, since armature '81" is not in contact with either of the contacts 38 or 38', andthe .semaphore will be4 moved to an intermediate or caution. po-

.sition, as indicated -at-'S.l .lVhen both re lays are energized, as shown at D, and C" in block 3, both coils 31 and 3 2 willbe .energized and the signal will be moved to e A proceeed position, as'indicated at S.

'The relative polarity or direction'of li'low ot current'through the coil" 8 of relay C (and the consequent movement imparted to the armatures 8a, 8b and 80),'will depend upon the positions of the pole-changing armatures 11b and 11c of track relays D associated withvthe corresponding block and the block in advance, these armatures being,

held up against respective contacts 40 and 41 when thecoils 11 of the respective relays `D are energized, and falling down upon the respective lower contacts' 42 and 43 when raised, contact 34, wire 35, wire 37, Wire 44 (which may be an overhead cable leadingte the neXt preceding unit), armature y11b relay D if raised, contact 40', wire 45',

wire 46, coil 8 of relay C wire 47', upper contact 41', armature 11 of relay D 'if `raised, and wire 48 which leads to themiddle point of a resistance 49 connected acrossthe power leads 4 and 5. The middle point cfa 'similar resistance 50 connectedacross the leads 4 and 5 adjacent the first described unit is connected by wire 51 with the wire 3G leading to the other end of signal sec nd?- ary SS. The wire 48 might be -conn ted directly with the wire 51, but since successive.

units are at a considerable distance' from one another, a material economy is eected by utilizing the power lines 4 and 5 for this portion of the return circuit. It will be noted that in the circuit just describedsince relay D of block 1 is deenergized .and the armature 11a has been dropped, the circuit .is open at 34', therefore'relay' C is -deenerlgized and its armature 8a has been dropped.- However, the coil 8 of relay C .is energized,-

since the armature 11n of the track relayl D of the home block Vor the block beyond block 1 atthe right (not shown) is raised "to complete this circuitlf In this circuit,

however, since the armatures 11b and 11c have been dropped by the deenergiz'ation of track relay D, the current iow will be reversed` through coilS (from that already described for coils 8') since the. circuit now runs from armature 1lb through contact 42, wire'47, coil 8, wire 46, and lower contact 43 to the other armature 11. .This willl reverse the relative polarity of the current energizing relay C and-cause the-armatures 8b and 8c to swing to the left against contacts 20'and 26, as shownin full lines. Inl the case of relay C', which isdeenergized, the armatures-8* and 8 have fallen to the intermediate conftacts 27 and 28. l V

Indescribing the operation of this. track apparatus,` we will first assume *that a stalled train, indicated at B, is in block 1.

This train will shunt the current flowing in rails and R of block' 1, so as to deenergize the track relay D anddrop the armatures 11, 11b and 11e, allas shown in the drawings. The dropping of thearmature 11?Ji will break the circuits-to both signal coils 31 and 32 and the semaphore S will show a stop signal. As

already described, the dropping of,` arm armature 11a will also break the energizing circuit for 4relay CA of the preceding block,

thus dropping the corresponding armature 83 and breaking Athe circuit to signal coil 32 so that semaphore S will give a caution signal. Since armature 11" of ltrack relay D is still elevated, the coils of relay C will` be energized, attracting the corresponding armature 8a, and both signal coils 31" and 32 will be energized holding the semaphore S vin 'proceed position. Therefore -a pro'- ceed signal will be given at the entranceotl block 3,I and a caution signal 'at the entrance of block 2, when a train occupies'block 1'.

The dropping of armatures 11b and 11c of relay D has resulted, as already described, in reversing the relative polarityof thefcurrent energlzing'relay C and swinging the' armatures 8?? and 8c to the left'so that a pul sating uni-directional current, termed the caution Y adverse polarity partial-blocklength current is flowing in block ,2. Since relay C is deenergized and the armatures 8b and 8 have been dropped against the intermediate'contacts 27and 28', a similar vrepeatingfcaution current of adverse polare is flowing in block 3 which is a .proy ceed block `for the wayside signals, butl a ity repeating caution blockH with relation to the train control mechanism; In each of Y blocks 2, and 3 there is a dead section of about 20 feet adjacent the exit vend'of` the A block, in which no eiiective current is flowl ing; In block 4 a pulsating uni-directional" current known as the normalpolarity fullmomie I `block-length current is'lowing, as in all other '.similarly conditioned j unoccupied vblocks of the track-way.

Referring now to Fig. 2 of the drawings,

the mechanism carried by the locomotive is diagrammatically illustrated, the locomotive being positioned over one of the dead sec- )tions of the track', with the @brakes applied. It will be assumedthat the locomotive is 1ocated in one of the blocks, lsuch as block 2 or block 3 in Fig. l, wherein adverse polarity current is being supplied tothe rails R and R in thatportion to the left of the connections 23 and 2.4. .At this particular time the section 'of the rails occupied by the front and 53, and are so wound that the currents.

induced in these coilsby the track currents running in the opposite directions'in the two parallel rails Rand R will be addedv collectively in. these coils, and will pass through wires 54 and 55 and charge the condensers 56,57 and 214. Obviously the directionor clarity of this Ainduced current will depen(A upon-the polarityv of the current` flowing in the rails, and atthe instance noted in the drawings no ciective current' at all will be induced in the coils 52, and 525. It will be noted that-the cores 53 and 53a, and the coils 52 and 52a thereon, are mounted over and around thefirst'pair of pilot wheels L. Vhen passing over one of the insulated joints l atthe. adjacent ends oftrack blocks, these wheels L'Will serve to bridge the joints and the coils being positioned Aover the wheels, no break inthe induced lcurrent will occur, that is, when similar currents are flowing in the adjacent blocks, as for example at--the junctionjot block 4' and the block preceding block 4.

, The improved power amplifier no'w to be described is designed to build up, in response to the weak currents induced in the coils 52- and 52", a pair of currents adapted'to alternatively control. the direct current' polarized relay-M. vThe power amplifier preferably includes a tube 58v having a single filament 59, energized fromthe battery 60 through leads 67" and 6 8`as shown, al pair of grids 6l and 62, and. a pair of plates 63 and 64. Assuming that a :so-called normal polarity pulsating current, (of the type indicated graphically in solid lines in ldiagram (2) of Fig. 5), is flowing in the rails R and R', an alternating current of substantially thetype indicated graphically in diagram (4) of-Fig. 5 will be induced in the coils 52 and 52a. substantially the characteristics of a pulsating direct current, each cvcle consisting '-grid 62. vWhen -tlfe so-called adverse po- This induced current will havev of ja comparatively long increasing pulsa.- I tion a7 ofl normal polarity, followed by a',

v practically instantaneous .reverse `ulsat1on,

or so-called peak cycle,indicate at y. A similar current, but voi' reversed polarity, as

70 indicated in diagram of Fig. 5, will be finduced in the coils 52 and 52a when the adverse polarity current is flowing in the rails R and R.

The pulsation m, when 'produced-by a 60 cycle alternating current,`corresponds to one of the pulsations of a pulsating current having airequency of v120, while thepeak cycle y will correspond to a pulsation of very higlrfrequency, for example 2000. The.v condenser 214 is tuned tothe high frequency of the peak cycle current, whereas the condensers 56 and 57 are tuned to a frequency of 120.

Assuming 'that' the induced current is flowing from coils 52 and 52 through wire 85 5 5, a positive charge will beimpressed upon `the lower plate of condenser 57, and a negative charge upon the lower plate of condenser 56. The successive positive charges impressed upon the lower plate of condenser 57,

formnegative charges upon the upper plate,

which in turn impress positive charges upon the grid 61. In a converse manner a series of negative charges are impressed uponthe larity current is owing in the rails Rand R', the current induced in the coils-52 and 4 52EL will be reversed, so that grid 62 will receive the positive charges and gridGI the negative charges.

The peak cycles induced by 'the ,sudden interrupting of the pulsating current in the rails will discharge' through the properly tuned condenser 21'4.v

' One circuit extends from filament 59, wire 105 67, battery 60, wire 82,\one actuating coil 83 'of the relay M, and wire`8'1 to plate 63. A similar circuit extends'from filament 59, wire 67, battery 60, wire 84, the-other actuatingcoil-SG of relay M, and wire 85 to plate .110

64. When the grid 61 is positively charged and. the -grid 62 isnegatively charged, a relatively` strong pulsating current will ow in the coil 83, and a relatively weak pulsating current will flow in the opposite direction in coil 86, 'as indicated graphically at aand. b respectively in diagram of Fig.

5. On the contrary,v when. the grid 6l is negatively charged, and the grid 62 is positively charged, the stronger pulsating current will flow in coil 86 and the'weaker current in coil 83, as indicatedgraphically at b and a respectively in diagram of Fig.

5. The relayM, in the example here shown, comprises the soft iron U-shaped core 80, having legs 78 and 79 about which the actuating coils 83 and 86 are respectively wound in opposite directions. The legs 78 and 79 lterminate in pole pieces 7 6 and 77 adapted to the neutral armature, hereinafter described. The neutral armature will be drawn up whenever the pole pieces are energized,'no

matter what their polarity may be. The

polarity of swinging armature 88 vis'permanent, and-it is pivoted at its upperl end near the neutral magnetic portion of core 80.`

Y ity, it will be swung alternately from side to The armature 88 having a permanent polarside as the poles ofthe relay M are reversed; When the currentof predominating strength is in coil"83the armature 88 of relay M will be swungover tov the right, as indi- .cated in vdotted lines in Fig. 2, and'- when the current in coil 86 isithel stronger, the armature will be correspondingly swung to the left as indicated in solidlines in Fig. 2.

The swinging.armature 88 of relay M, when swung lto the right by currents of normalpolarity, will engage the ix'ed conltact 90, and when swung to the left byvcur rents of adverse polarity, will engage the fixed contact 91. Whileswinging from one of' these positions to the other the armature'- 88 will momentarily engage an intermediate contact92. The relay M is also provided with a neutral armature comprising two-contact bars 89 and 97. When the relay M is referred to.

er'iergized,` the armatures 89 and 97 will be held up against the fixed `Contact members 93 and 95 respectively, and whenthe relay isdeenergized the armatures will fall into engagement with the'iXed contacts 94 and 96. When' armature 97 is raised it-also engages a" second fixed Acontact 95', hereinafter The electrical `circuits' of the locomotive are energized by the generator G mounted thereon. One terminal lof thegenerator is connected through'wirev 98 withl the pivot ends'of armatures 97 and 89, and the other .side of the generator is connected by wire 100 with one side. of each of the signal lamps 1 101, 102, and 103, adapted to give, respectively, green, red and yellow signal indications; The other'sides of these lamps are connected, respectively, as shown, with the fixed contacts 90, 92 and 91.- Red lamp 102v is also connected with fixed contact' 96, as

shown. Under normal :running conditions,

l armature 88 will be swunoP over tothe left against fixed contact 91, thus closing a circuit vsimilar to that just described through When the train the yellow caution signal light 103. It will be noted that in passing from its `right hand to leftvhand position, the armature88 willl momentarily engage the contact 92, 4thus giving a red flash of lamp 102 as a further `warning signal. When no induced current is being'received by relay M, the armature 97 lwill fall into'engagement with contact 96, and a circuit through the red danger or stop light -102 Y tained.

will'be completed and main The valve V for controlling the brakes, comprises a vvalve block or chamber 104in which is slidably 4arrangeda double-seating angularA slide member 105, -having an oper ating rod106 to which is vaiixed a plate 107l adapted to be held Vupby the magnets 108 against the action of the spring 109', which tends to move the -valve member 105 toits lowerfposition, as shown in the drawings. Normally, with the brakes releas'ed,^"the slide member 'willl be held up by themagnets 108 with the plate 107 in its dotted'line po,-

sition. At the upper end ofrod 106 is pivoted a contact plate 110, adapted in normal raisedrposition to engage the fixed .contact 111, and when lowered, as shown in the drawings, engaging theiixed contact 112.

When the valve member 105 is raised to ynormal running position, communication isestablished from the air reservoir pipe 113, through ports 114 and 115 and the pipe 116 to the brake valve 117. .When the magnets 108 are deenergize'd, thespring 109 forces the slide member 105 down into the position shown inthe drawings, to c lose the air reservoir ports 114 and l115 land to establish communication from thetrain line pipe 118, through pipe 119 and port 120 with the outlet 121 to the atmosphere. It will be ob- `vious from thedrawings that when the magnets`108 are energized to raise the member 105, the port 120 willbe closed to prevent train line exhaust, andports 114 and 115 will be opened to provide reservoir pressure to the brake valveto hold the brakes vreleased. An outlet 122 is provided to allow the escape of any airfthat may be trapped above the top of the sliding member 105. As the slide member 105 rises it will close the opening 122 to prevent thej escape of train line air. YVhile the type of valve just, describedl is preferred, it will be .apparent that other `suitable types of brake valves might be used, the movements of the valve vmember being actuated by the magnets 108 and thc return spring 109.

As long as relay M is-receiving current, either of normal4 or adverse polarity, the armature 89 will be held up against .fixed contact 93, anda circuit for energizing the, releasing magnets 108 will be completed, as follows: Generator G, wire 98 to the pivot end of the armature 89, contact 93, wire 123, wire 124 to the pivot end of swinging contact [plate 110, fixedA contact 111, wire 125 to the coils of magnets-108, and wires 126 and 127 back to the generator Gr. When- .ever the armaturel 89 is momentarily re-` leased by the deenerg'ization of relay M, the

circuit will be broken at 93,- thus deener' gizing magnets 108 and .causing brake application unlessthis action is forestalled by manual. operation of' the acknowledgmentw switch 128. TheA armatures 89 and 97 are slow-acting and even a momentary dceneigization of the magnets 108 by break' age ot-- the lactuating current at. 93 will be 'suliicient to permit the highly compressed springv 109 to move valve 105 downwardly and effect a brake applic-ation.` It-'isonly necessary that-spring 109 act quickly enough to break the circuit at 111 before the contact been .broken atv111' it canonly be reestablished by manual manipulation ot one of the switches 135 or 141;n In the example i here show-n, the acknowledgment switch 1 28 being sufficientlyquic'k-acting to break the .circuit at 111 while armature 89 is passing is 'in the form or' a spring released plunger adapted to close the gap between the contacts^129` and 13.0, connected by' wires .131

and '132,- respectively, Vwith the wires 98. and 124, thus forming' a shunt circuit about the relay M. By pushing in the switch 128 while the locomotive is passing over a deenergized section of the track, the. holding l circuit for `magnets 108 maybe vmaintained while the armature 89l is out ofcontact with the li-xed contact 93 or 94,-the. magnets 108 from contacts 93 to contact 94, if the switch 128 is not closed.

If the brake application is not forestall'ed, a circuit will `be completed .through the brake signal light 133, which may convenwill give a purple indication, as long as'the` iently give a purple indication, asfollows: From generator Gr through wire 98, armature 89, contact 94, wire 123, wire 124, swinging contact plate 110, liXred contact 112, wire 134,'4purple light 133'and wire 127 back to the generator. The' light 133 In case .a .brake applicationis not forestalled in time before passing over a dead `section, of the track by the manipulation of switch 128, provisions areimade'whereby-the brakes may be reset p rovided` theltrain is 'merely in a caution block orl a: repeating caution block, that is,'providing the relay M is receiving induced current of either nor- 136 and 137 a resetting circuitlthrough the 4 magnets 108 will. be completed as follows:

From generator G to wire 98, armature 97,

contact'95, wire 138 to contact 136, resetting switch 135, contact 137, wire 140, wire 125,1nfagnets 108 and wires 126 and 127` back to the generator G. After the brakes havel oncebeen reset, the contact plate 11-0 will be moved up against contact 111, thus completing the normal' brake releasing circuit, and the switch 135 may then be re-l leased. However, if the brake application takes place under stop conditions, that vis whenI the locomotive is in'one of the-,dead sections at the exit end ot a caution block, or is in an occupied block, the relay M will .be completely deenergized andthe armature 97 will Vnot contact with the fixed Contact 95,-so thatv the resetting switch 135 will be .ineffective to reset the brakes.' In such an event, 'the brakes can only be reset by manipulation ofk the .switch 141 which is located beneath the locomotive, or at a point 'which is only accessible afterA the train has been brought to a complete halt. The circuit through resetting switch 141-is as follows: VFrom generator G, through wires 131 and 142,' to fixed contact 143, switch 141, `fixed' ContactV 144, wire 145, wire 4140, wire 125, magnet coils 108'and wires 126, 127, back to the generator G. l

l The usual double-heading cock .146 is provided in the train pipe line 118, and a train stop failure cock 147, under seal, is provided for normally `closing the reservoir pipe 148 and opening the `train'line exhaust pipe 119. describing the -.general operation of this mechanism, I will first assume the condition shownin Fig.' 1 of the drawings, a train B occupying stop block 1, and shunting the track circuit therein so as to dcenergize the trackrelay D. A train lapproaching from the right will pass through proceedblock f4, whichis still receiving normal polarity full-block-length current, with theI green running light showing in the cab, and no brakeapplication will take place. As'tiis train enters repeating caution block 3, as indicated at E, the wayside semaphore'signal S will still give a proceed signal, but since adverse .polarity current is being sup-- l plied to the rails in block 3"and adverse pol-k arity current will be inducedin the locomotive to operate the relay M, the armature 88 will be swung from itsv right to its lett position so that the'green `lightwill be eX- tinguished and ayellow signal will be givenby the lamp 103A This practically instan-j ytaneous change in polarity ot coils 83 and -86 causes a reversalot' the position of arma- .ture 88, but will not deenergize the coils suticiently to release the neutral armatures 89 and 97 which will remain up in contact with the iX'ed contacts 93 vand 95 respectively.l This will be a caution signal to the operator that an obstruction occurs in the second block. ahead, or perhaps in the first block llO s lwill be observed at semaphore S and also ahead in case of a train backing thereinto.

lIt will also indicate to the operator that a brake applicationv will take place at the exit end of this block 3, in which he is now located, and he must forestall this application lby closing the switch 128 as the train proceeds across the dead section between the vpoints V23, 241 and the exit end of. block 3.

If the operator manipulates switch 128 in time, no brake applica-tion will 'take place, and as he enters block 2, ,a cautionsignal the yellow caution light 103 will continue to showk within the cab. This will inform the temporary ,energization ot'y lamp 102'..

the operator that the obstruction is within the next succeedingblock. It will also be' noted that as Athe train passesover the dead track section, or brake application point, at the end of block 3, the armature 97 willpbe released to' make contact with the fixed con1 tact 96 and give a'red flash or signal through This is a further 'warning to the operator that the brake application point is being l crossed, and when the yellow signalresumes its caution vindication withinthe cab, the operator will know that he may release the switch 128;4 In case the` operator neglected any portion of block 1. Consequently a brake applicationl will immediately take place ,unless orestalled by closing the switch 128( If the automatic brake-applicationis forestalled the operator may bring the'train to a halt in the usual manner by manual operation of the brake valve 117 upon observing the continuous red stop indication. If the automatic brake application is not forestall'ed Abyvclosing switch 128,v

the brakes will be immediately applied, and the vswitch 135 will,now be ineifectivelto reset the brakes sincearmature 89 is no longer in contact-with iixed contact 95, the relay M vbeing deenergized. `The train will now'be stopped and thebrakes can only be reset by manipulating the switch 141 which, is not accessible from thecab. vUpon enter-- ing stop block 1, the wayside semaphore.

signal S will also give a stop indication. It will be noted that a yellow caution signal will be given in the cab throughout both of the two blocks preceding the occupied block, and that a red flash will take place at the exit end of each of these blocks. A brake application will also take place at the\ exit end of each of these blocks, unless forestalled by using switch 128. If the `yellow l lsignal resumes after a red ash, the operator will know that he is still within a caution block and may proceed if on-l the alert. Whenever thebrakes are being applied, the purple light 133 jacent blocks the track circuit has been suddenlyyshunted or broken by an open switch, a broken" rail or an advance train backing into that block.' VThis brake applicationl occurs -because the advance track relays contacts will drop, and the moving of the pole changing armatures onthe line relays from ,normal to adversegpolaritjy,Contact position `will provide an intermittent loss of track current duringsuchfchange, and-the consequent momentary dropping of armature 89 on the engine willv break the vmagnetcircuit will signal thatffact to ithe operator. y a l In case an enginefhas fullyV entered anA advance block, .and a yellow light begins to show, 'with an immediate brake application` this indicates that in one of the next two adand cause 'the brake l application. .The

ybrakes may now be'reset by meansof switch 135 in case the engineis merely within a caution block, butA if the obstruction occurs within the lblock then occupied, this switch 135 will; be ineffective and the train 4will be stopped. In any case, a shunting of the track circuit'byfan obstruction-within the same -block' occupied fby the engine will'l cause an immediate`brake application,jandthe brakes cannot be reset until the train has i been halted. Y Any temporary loss of track current and consequent deenergization or relay M will result in the dropping of armatureV 89, and

`thus breaking the energizing. circuit for magnets' 108 with a resultant .brake application. However, vwhen the 'locomotive passes from one block energized with normal polarity current to an adjacent .block energized withvadverse polarity current, l(fory A'example from block 4 to block 3'), although the polarity of relay M will be reversed to swing the armature 88 from right to left, the relay will be lcontinuously, energized sufficiently to maintain the' neutral armature 89 in' its 'raised position so that the energizing circuit to magnets 108 will not be broken and'no brake-,application will take place.

It will thus be observed .that automatic i brake applications take place at the exit. ends of both caution and repeating ca ution4v blocks preceding an occupied block, and that such brake applications take `place imme-d diately at 'any point upon the' track if the" track circuits are shunted or broken by any cause in either the block occupied by the engineer in either of the next two advance blocks. These brake applications may be forestalled, or the brakes temporarily reset in case the obstruction or danger point is within one of the following blocks, but not if the danger point is within the block then i Itwill be evident from'the foregoing deoccupied. The system necessitates successive acknowledgments to prevent brake applications at the end of each block when'the train is running under danger conditions, that is, followingV a train 'in the same block ,or "in one of the neXt two advance blocks. In case the trains are running within the same block and the forward train proceeds into an advance block, the block occupied by the following train will change lfrom stop to caution conditions and a brake application will occur immediately unless forestalled by switch 128. The brakes may, however, be reset lby 'the running reset switch 135.

scription that by holding ythe switch 128 closed brake applications are prevented, and it is only intended that this switch shall be closed momentarily, to bridge over the intervals when armature 89 is moving from oneoperative position to another. It will be apparent that if this switch 128 were held closed permanently, or for an unauthorized length of time, many of the operations nvolved in this control system would be avoided. To prevent this, the modified form :sel

ofacknowledgment switch shown in Figa 3 may be used, if considered necessary. The stem 149 extending from switch` plate'128 carries the valve member 150, which lits wit-hin the-valve-block 151so as to normally close the port 152 communicating withpipe 153 which leads from the air-brake system.

When switch 128is closed, the valve 150 be lifted to permit a small escape of air.

through the. port 1,52, which will bleed the air system, so that if this vswitch 128 is held closed for any material length of time (and the valve-150 thus held open), a brake Vap- .ilication will occur due to the loss of air through port 152.

It is to be notedthat when traliic conditi-ons change fronr danger to either' caution or clear, th e engineer must again acknowledge, since the armatures 89 and 97 move from their lower to their upper positions upon such a change in traffic conditions Qand unless the engineer acknowledgesole lnoid 108 will become deenergized, as already described.

It will be noted that the track electrifica-- tion is-produced from a single alternating y current,and that only a single pulsating current will flow at any one time in the rails of any block, and only a single induced current is utilized to controlthe ymechanism on the i fiowing'in the same direction, or are of the cautionr or repeating caution blocks will` locomotive or other vehicle. At any one instant the currents inall proceed blocks are same polarity, whereas the currents in at that instant flow inthe reversev direction, or be of the opposite polarity. The induced current in the vehicle will change its direction of flow or polarity in accordance with the position ofthe. vehicle over the rails of either a proceed or caution block. Whenever the relay M is deenergized to drop the armature 89, a brake-application will occur (unless forestalled). This will occur whenever'conditions change from either proceed -or cautionto stop Also, whenever relay M is again energized to raisev the armature 89, a brake application will take place, In

other words, whenever the vehicle passes from an electrified to a non-electrified or power-olf section of trackway, or when it passes back onto an electrified section, a

. brake "application will occur unless fore-` stalled. -Such conditions will4 he indicated by the change from either a. green or-yellow to a red indication, or the change from a red indication back to a yellow or green. Then-l ever the purple light is illuminated a brakeapplication is taking place. In such case, if a yellow or green light is burning, the reset switch 135 will be effective to. release -the brakes while the vehicle is running, but

ifvthe red signal persists, the reset switch 135 will be inoperative, and the switch 141 o trols both the cab position-indicating signals and the brakecontrolling mechanism. K

This system makes possible the bringing of advance information of the conditions existing in advance-blocks to the operator by. uneans ofcab\ lights, substantially as found along the wayside, and makes possible the eventual discard of all main track wayside signals. It will' be noted4 that the second block preceding an' occupied or stop block is simultaneously a proceed block in so far as the wayside or semaphore signals are concerned, and a repeating caution block with relation to the cab-position-indicating mechanism and the brake control mechanism. By properly interpreting the combined signals given by the semaphorcs and by the cab lights, the A operator can estimate with fair accuracy the' distance from the stop point, that is., he will know approximately vwhether he is' one or two blocks distant `thatblo'ck.. A single relay in the cab confrom the Imation where stop conditions prevail. i

llitli vehicles so equipped, upon entering '.non-electrilied tracks :from electrified tracks, the automatic brake controlling ap# paratus may be completely released by teniporarily closing the forestalling switch 128.

vThis acknowledgment switch must again be operated when the vehicle again enters the electrified track in order to prevent a brake application. In this latter case, if the acknowledgment is neglected, the brakes may be reset by operating the running reset switch 135.

As a positive check against foreign current interference during a stop condition, a

. brake application occurs during the movement ot armature 89 from'lower cont-act 94 to upper contact 93, when the vapparent con` ditions change from a stop toa caution or to a proceed circuit; thisalsovguards against an engineer acknowledging a stop and contmuing at high speed 1n the same block with another train, since the advance -train passing into the next block circuit provides in the rear block caution current to the fast moving train thereinand gives a brake application .to such train at any part of that block so that the secondtrain has as much braking distance as possible.

The running reset circuit through switch 135 will avoid an actual stop ofthe train it the operator is alert to operate this switch, but'this action will not actually interfere with the brake applying means, since there iscontinuous possibility of, further brake applications within the same block that has already given a brake application condition.

VIn other words, the closing of' switch 135 will be eltective toA permit the release vot the brakes, but this circuit willnbepbroken even though switch 135 isV `closed .in case relay is deenergized and the armature 89 lisl dropped. Thus the stopping of the train under actual danger conditions cannot be' avoided by closing the switch 135` I claim:

l. In combination with a trackway divided into blocks, a vehicle adapted to travel on the rails of the trackway, `brake controlling means on the'vehicle, "and positionindicating signals on the vehicle, a, source otA alternating current, means for supplying a single current derived from .thisvsource to each block of the trackway, means for reversing the polarity of this current in a por- .tion of the block and cutting oit the current proceed, caution and stop signals, a source of alternating current, means forsupplying a'single current derived from this source to each block of the trackway, means for reversing the polarity ofthis currentiin a portion. ot" a block and cutting olf the current in thel remainder of the block in response to advance track conditions, and means on the vehicle for receivinfr a singlevinduced currentffrom therails which is broken or changes its polarity'in conformity with the track current, and utilizing this current to control the position-indicating means.

3. In combination with a trackwaydi'- vided into blocks, a vehicle adapted to travel on the rails vof the trackway, and means, on the vehicle controlled by currents induced from the rails, asingle source of alternating current, connections for transmitting from this source a separate pulsating unidirectional current to the rails in each of a plurality of adjacent blocks, and means for reversing the direction ofiiow of this pulsat: ing current in one block in response to stop conditions existing in an adjacent blockU 4. In combination with a trackway divided .into blocks, a vehicle adapted lto travel onthe rails of the trackway, and means on the vehicle controlled by currents induced `from the rails, a single source of alternating current, connections for trans- 'mitting from this source` a separate pulsating unidirectional current tothe rails in each of a plurality of' adjacent blocks, andmeans vactuated in response to stop conditionsexisting in an advance block for reversing the direction of flow of this pulsating current in the preceding block.

'5. In combination with a trackway di-v vided into blocks, a vehicle adapted to travel on the rails of the trackway, and means onthe vehicle controlled by a single current induced from -the rails, a source of alter-` nating current, connections 4for transmitting from this source a separate current to the rails in each lof a plurality of adjacent blocks,

y and means actuated in response to stop conditions existing in an advance blockfor j reversing the polarity ot the 'current in each of the two preceding blocks.

6. In combination with atrackway di- A vided into blocks,l a vehicle 'adapted to travel on the rails of the trackway, and

means on the vehicle controlled by a single currentpinduced from a single current in the rails, a source of alternating current, connections for transmittingffroni this source to each of a plurality of adjacent blocks, either a pulsating current of normal polarity to the full length of the block, or a pulsating current of adverse polarity to a portion ot' the block, and means for reversing the polarity of the current in one block in response It sliep conditions existing in an advance 7. In combination with a 'trackway divided into blocks, a vehicle adapted to travel on the rails of the trackway, and` -means on the vehicle controlled by a single current induced from a single current in the rails, a source of alternating current, connections for transmitting from this source to each of a plurality of adjacent blocks, either a pulsating current ot normal polarity to the full lengthlotthe block, or a pulsating current of adverse polarity to a portion ot' the block, and means for reversing the polarity of'the current in one block inresponse tostop conditions existing in eitherof the next two advance'blocks. l

8. In combination with a trackway di-l videdl into blocks, a vehicle adapted to travel on the rails of the trackway, and means on the vehicle controlled by a single current induced from a single current in the rails, a source of alternating current,

connections for transmitting from this source. to each of a plurality ot adjacent blocks, either a pulsating current 4of normal polarity to the full length of the block, or a pulsating current of adverse polarity to a portion of the block, and means actuated in response t'o stop conditions in an advance block for reversing the polarity of the current in the two preceding blocks.

"9. In combination-with a trackway divided into blocks, a source 4of` alternating current, means 4for supplying from this source/a single uni-directional pulsating curr rent to the rails in a block, and means for vchanging lthe polarity of this current vresponse to changes in advance ltrack conditions, a vehicle adapted' to travel on the rails, means on the vehicle for receiving `an .induced current conforming to theI current then existing in the rails', amplifying means on the vehicle responsive to the induced current, a relay having t`wo actuating coils energized from the amplifying means, the relay having an armature movable to a plurality of posit-ions and a.plurality` of position-indicating vsignals controlled by thev armature of the relay.v A

' l0. In combination with a trackway di,- vided into blocks, means Jfor suitably electrifying this trackway, 'a vehicle adapted to travel on the rails of the trackway, and brake-controlling mechanism on the vehicle, means controlled electrically from the traclrway whereby when stop conditions exist in an advance-block, a brake application will take place at the exit end of each of the two preceding blocks. and runningieset means` on the vehicle whereby the brakes may be released following a brakeapplication in the second preceding block, this means beingineiectiveA after the vehicle has entered the block in which stop conditions exist.

1l. In combination with a trackway di'- -vided into blocks, 'means for suitably electrl-fying this trackway, a vehicle adapted to travel on the rails of the trackway, and

brake-co ntrollingmechanism on the vehicle,. l

tion is, not toi'estalled in the second preceding block, this reset means being incii'ectivc attcrilie vehicle has lentr-:red the block in which stop conditions exist.

12. ln ,combination with a trackway divided ingto blocks, means for suitably elec` trifyingl this traclrway, a vehicle adapted to .travel on the rails of the traclrway, and

position-indicating signal mechanism on the vehicle adapted to give eitherproceed, caution or stop signals, means controlled from the trackway in response to stop condit-ions existing vin an advance block for causing a caution signal to be given while 4 the vehicle is in the next preceding block, also a repeating-caution signal to be given .while the vehicle is in the second preceding block, and a stop signal to be momentarily given "at the end of this second block.

13. -In combination with ,a trackway divided into blocks, means for suitably electrifying this trackway, a vehicle adapted to travel on the rails of the traclway, and position-indicating signal mechanism on the vehicle adapted togive either proceed,

-caution or stop signals, means controlled from the ti'ackway in response to stop con- 'ditions' existing in an advance block 'ior causing a caution. signal to be given while the vehicle vis in the scond block preceding ihe advance block, and a stop signal to be momentarily given at the end of this second block.

14. In'coi'nbination with a trackway divided into blocks, a vehicle adapted to travel 0n the rails of tlietrackway, brake controlling means on\tlie vehicle, positionindicating signals on the vehicle, a generator on the vehicle for supplying actuating current to the brake controlling means and the position-indicating signals, a sourcejof alternating current, means for alternatively supplying from this source a pulsating current to the ull length of the rails in each block or a pulsating current of reverse polarity lto a portion of 'the rails only,

meansacting, in response to stop conditions existing in an advance block for determining the polarity of the current supplied to the block, means onthe vehicle for receiving a single induced current from the currentl then existing inthe rails, and means n the vehicle 4for utilizing this current to control the brake-,applying means and the position-indicating signals.A y,

l5. In combination with a trackway divided into blocks, a vehicle `adapted to travel on the railsot' the trackWay, brake con` trolling means on the vehicle, position-ind`i-- eating signals on the vehicle, a generator on the vehicle for supplying .actuating current to the brake controlling means and the position-indicating signals, a series of Wayside signals one at the, entrance to each block, av

4 source of alternating current, means for supplying from this source either a pulsating current of normal polarity to the tulllengtli ofthe rails in each block or a pulsating current of reverse polarity to a portion ot the block rails only, means acting in response to stop conditions existing in an advance block for determining the polarity of the ycurrent supplied to the block and toi-also actuating and controlling the Wayside signals, means on the vehicle for receiving a single induced current `from the current lthen existing in y the rails and means on the Vvehicle or'utilizing thais current to control the brake-applying means and theposition indicating signals; y

16. In combination with-a trackway divided into blocks,\a vehicle adapted to travel on the rails of the trackway, and means on f the vehicle controlled by currents induced tromthe rails, a single source of alternating current, and al means :tor each block for transmitting from the alternating current aI pulsating unidirectional current to the rails of the block, comprising a transformer having a primary energized by the alternating current, and two secondaries, and means actuated by the alternating current from one secondary tor interrupting the current from the other secondary.

17. In combination'with a trackway divided inio blocks, a' vehicle adapted to travel on the rails ol the trackway, and means on the .vehicle controlled by currents induced from the rails', a single sourceot` alternating current, and a means for each block for transmittingfrom the alternating current pulsating unidirectional current to the rails of the block,'comprising a transformer having primary energized by the alternating current, and two secondaries, a rotary interrupter actuated by the .alternating currentI from one secondary, the interrupter rotating synchronously with the alternating current `and servinggto transmit to the rails only similar portions ot'- each cycleof thecur` rent from the -other secondary.

18. In combination with a` tnackway div'vided into blocks, a vehicle adapted to travel on the rails of the trackWay, and means on tli'e vehicle controlled by currentsinduced from the rails, a single source of alternating current, and a means for each block for transmitting romthe alternating current ak pulsating unidirectional current to the rails of the block, comprising a transformer having a primary energized by the alternat- 4ing current,- and three secondaries, an interrupter actuated by the current induced in one secondary, and a transformer for changing the phase ot the current induced in a second secondary, the interrupter serving to transmit to the rails only similar portions of each cycle ofthe currents induced in the second and third secondaries.

19. In combination with a trackway, a vehicle adapted to travel on the rails of the Itrackway, control nieans on the vehicle responsive to a current induced from the rails,

a source of alternating current, means tor` transmitting from this source a pulsating unidirectional .current to, the rails, and means for reversing the direction of this pulsating current flow in one portion of the traekway in response to stop conditions existing in an adjacent portion of the trackway. t

20. In combination with a trackway divided `into blocks, a Wayside signal at the.

entrance to each block, a vehicle adapted to for reversing the current in one block in response to advance track conditions.

RUSSELL vArPLnroN.

CERTIFicATE 0F CORRECTION. y L

' ment No. 1,104,116. Granted March s; 1929,11y

RUSSELL v. APPLEToN.

It is hereby certified that error appears inthe printed specifiction of the above numbered patent requiring correction as follows: Page 9, line 100, for the wordV "signal" read "single"; and that the said Letters Patent should be read with .this correction therein thatthe same may conform to the record of the caneY i Patent Office.-

Signed and sealed this 2ndA dayof April, A. D. 1929.

f -M. J. Moore,

V(Seal) Acting Commissioner of Patents. 

